


curative treatment

by LuthienKenobi



Category: Teen Wolf (TV)
Genre: Angst, BAMF Alan Deaton, Canon Compliant, Episode Tag, Episode: s03e19 Letharia Vulpina, Gen, Hurt Scott McCall (Teen Wolf), Hurt/Comfort, Mentioned Stiles Stilinski, gratuitous science content
Language: English
Status: Completed
Published: 2021-01-19
Updated: 2021-01-19
Packaged: 2021-03-18 04:26:39
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,413
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28861029
Author URL: https://archiveofourown.org/users/LuthienKenobi/pseuds/LuthienKenobi
Summary: If the spirit was looking to maximize horror and fear, terrorizing Scott while inhabiting the body of his best friend was certainly an effective method of doing it.He supposed he shouldn’t be surprised. The creature had existed for centuries—perhaps even a millenia. It was only logical that, in all that time, it had learned to hone its craft.Fortunately for them, the Nogitsune wasn’t the only one who’d honed his craft.
Relationships: Alan Deaton & Scott McCall
Comments: 13
Kudos: 22





	curative treatment

**Author's Note:**

> This is a significantly expanded version of a fic that I originally wrote for Fictober 2020, for the prompt "that was impressive".
> 
> Beta'd by [momentofmemory](https://archiveofourown.org/users/momentofmemory), who deserves a huge thank you for her endless patience during the far-too-lengthy edit process for this one!

Deaton was running out of time.

It was ironic, really. The majority of the trip—including entering a Yakuza base of operations under false pretenses—had gone nearly as smoothly as he could’ve hoped. Even smuggling the sample vial of lichen through customs in his medical bag had gone over with very little fuss. 

But nothing ever progresses entirely according to plan. 

The first sign of trouble showed itself on the connecting flight out of Sacramento. According to the scheduled arrival time, they were only a half an hour away from their destination when the pilot announced that they’d be experiencing some turbulence, due to an unexpected thunderstorm that had formed to the north.

That turned out to be an understatement. 

The storm delayed their arrival by nearly a quarter of an hour, but once they were in the vicinity of the airport, the pilot announced another warning: due to frequent lightning strikes in the area, the plane had not been cleared to land. 

Deaton felt a sense of growing dread: the forces of nature often reacted in sympathy to intense foci of supernatural activity, and such events had often caused storms in the past. When the supernatural activity in question was a pitched battle between ancient spirits known to harness electricity...

If the storm dissipated long enough for the plane to land, he might already be too late.

Another agonizingly long quarter hour later, the jet landed without further incident. He checked his phone as soon as the plane touched down, but no there were no new calls or messages. He didn’t have enough information to know if this was a sign that everything was going according to plan, or if it was the exact opposite.

And as much as he wished to leave immediately, there was still nothing he could do. The plane sat unmoving on the tarmac, but due again to the lighting, the passengers were not allowed to deplane.

The universe wasn’t cruel or unfair, he reminded himself—those concepts only truly held meaning among sentient beings, while the natural world traded instead on cause and effect. Sometimes, however, the sheer irony of events seemed pointed. Mocking. To be so close to Beacon Hills, to the people that needed him, but to be trapped here…

He knew what it felt like to arrive only in time to sift through the rubble. It was not an experience that he ever wished to repeat.

If they followed the previously established pattern, the Oni would’ve manifested as soon as the sun fully set—nearly an hour ago now. They weren’t inherently a danger to anyone except the Nogitsune and its host, but if someone tried to interfere with their task, he knew they would show no mercy.

Given that the Nogitsune’s chosen host was Stiles Stilinski, Deaton knew the young Alpha would certainly interfere.

Deaton’s carry on and medical bag were both in hand, ready for the moment the boarding doors opened. Twenty interminable minutes later, they finally did.

Deaton sent a quick text to Scott, telling the teen to meet him at the clinic, then started the final stage of his journey. 

Driving straight into the heart of the storm.

The roads were treacherous, and despite driving faster than was strictly advisable, he arrived later than he would’ve liked. Speed was paramount, so he parked in front, mentally running through the steps necessary to prepare a suspension from the lichen. 

Intramuscular injection would be preferable. The spirit likely puppeteered its host by manipulating the electrical impulses controlling the musculature and brain, so administering the solution to the neck should allow the effect to take hold quickly. Suppress the parasite’s ability to control the nervous system, and he’d effectively suppress the parasite itself.

As far as the preparation of the solution was concerned, an aqueous vehicle would be best. Include a small amount of ethyl alcohol to break down the lichen, hopefully releasing the toxin into the body at a faster rate—

The harsh groans and labored breathing of someone in pain greeted him the second he entered the clinic. 

His blood ran cold. Apparently, his fears on the plane had not been unfounded after all.

What he didn’t hear were the sounds of a fight, which meant that the Oni hadn’t yet materialized inside the clinic. With a little luck, then, they still had time. 

He gripped his medical bag tighter and hurried towards the back room, closing the gate behind him as he did so. From what Scott had told him, the Oni were eventually able to break a mountain ash barrier, but it took energy and time.

Tonight, time would be invaluable.

He rounded the corner to see Scott, rain-soaked and in visible pain, braced against the end of the exam table and fully impaled with what appeared to be an ancient Japanese sword. Kira was tugging on the hilt, but in what he assumed was fear of hurting Scott further, she did not use the amount of strength required to cleanly remove it. Scott didn’t scream, but his face contorted in response to the miniscule shift of the blade moving inside him.

The sword remained lodged in place. 

Deaton was already in the middle of rushing forward to assist when Stiles—no,  _ the Nogitsune _ —grabbed Kira by the wrist and threw her into the table. Her head connected with the metal, and she slumped to the ground, unconscious—even if the action itself hadn’t been so unlike the Stiles Deaton knew, it demonstrated the sort of strength only possessed by supernatural beings. 

The dread he’d had an inkling of before now settled deep in his gut, and Deaton reversed his movements and stepped back into the shadow of the doorway. Short of breaking the mountain ash barrier and letting the Oni in, the only hope of subduing the spirit inhabiting the teenager was the small sample of lichen in his kit that he had traveled over 5,000 miles to find.

And it wasn’t ready. 

It wasn’t that it would take long. Between the items in his medical bag and the supplies in his office—mostly consisting of overflow from the fully stocked exam room, but sufficient for his purpose—he should be able to prepare the mixture quickly. But even a handful of minutes was still  _ time _ .

He’d been so close to arriving in time to stop this from happening. If he’d booked an earlier flight, if the storm hadn’t cropped up so quickly, if he had driven just a little faster…

Deaton steeled himself, because none of that mattered right now. Because dwelling on a sequence of events that didn’t occur could only serve to distract him from the task at hand.

According to all the information he had, Nogitsune gained power and strength by feeding off pain and its associated negative emotions. With the Oni bearing down on its location, the spirit would be desperate for the power to match them—it wouldn’t kill Scott until it had devoured every last bit of fear and pain available for the taking. If he worked quickly, he would have time to prepare the solution before the Nogitsune took any permanent action.

It was a cold comfort. 

When the Nogitsune’s back was turned, he slipped into his office. He caught a glimpse of Scott’s face as he passed and saw the dread that he was feeling mirrored in Scott’s eyes. 

Scott seemed frozen in shock—no flash of recognition, or other hint that he knew Deaton was there. Which was for the best, he knew that. Knew that any movement or sound that gave away his location could have disastrous consequences, for all of them.

That knowledge didn’t make it any easier to leave Scott alone and afraid. To let him believe no one was coming for him.

He spared one last glance at Scott before setting to work, a decision that was at once both clinical and self-indulgent. As a doctor, he needed to assess the teen’s condition—it was the least he could do, as a full examination was currently out of the question. As a person forced to watch someone he thought of as a son be terrorized by an ancient spirit of strife and chaos…

The last thing that he wanted to do was leave.

The legends weren’t entirely in agreement regarding the nature of Nogitsune, but most indicated that they thrived in an environment of horror and fear. If the spirit was in fact looking to maximize these emotions, terrorizing the young man while inhabiting the body of his best friend was certainly an effective method of doing it.

He supposed he shouldn’t be surprised. The creature had existed for centuries—perhaps even a millenia. It was only logical that, in all that time, it had learned to hone its craft.

Fortunately for them, the Nogitsune wasn’t the only one who’d honed his craft.

Everything depended on speed, so he set to work immediately, grinding the lichen into a fine powder. Or rather, paste, as the lichen was still fresh and held a fair amount of liquid. 

In the other room, he heard the ancient chaos spirit speak to Scott with a mockery of a best friend’s concern. “You okay?”

“Please, don’t—stop.” Scott’s reply was more accurately breathed than spoken, and Deaton’s heart broke. He had, of course, seen the young man terrified on numerous previous occasions, but—

But this was the first time he had ever heard him beg. 

He hated it with every fiber of his being.

Forcing himself to focus on his task, Deaton tipped the ground lichen back into the jar, scraping out every last bit of green paste. There was an inherent danger in using all of the material he had, but this sort of thing had not yet been quantified by science. If he skimped during the first preparation and it wasn’t enough, he likely wouldn’t survive long enough to try again.

In the other room, Scott screamed.

Deaton’s hand tightened around unyielding glass.

He didn’t increase the speed at which he was making the solution, because the risk of catastrophic error or revealing his location was still too great. Because any misstep could cause the death of all three teenagers trapped in the adjacent room. 

He was, effectively, as trapped as they were.

Hands that refused to shake measured out the proper amount of distilled water. Added it to the container. Measured a smaller amount of ethyl alcohol.

The Nogitsune’s quiet, measured voice overlapped with Scott’s agonized cries that started and stopped in short bursts. “Does it hurt? Hey, look at me.”

Deaton wanted nothing more than to tune it out. Instead, he listened closely, parsing the various sounds of pain. Ready to intervene once the situation turned dire enough to require it.

He wasn’t sure what he would do if that moment came too soon.

He added the ethyl alcohol, capped the jar, and shook it vigorously. The ground lichen swirled through the liquid, tinting it a light and cloudy green. Outside, the spirit continued its monologue, poisoning the air just as surely as the lichen poisoned the alcohol.

“A Nogitsune feeds off chaos, strife, and pain,” it said, clearly pleased with itself. Enjoying the power it held over its terrified victim. “This morning, you took it from Isaac, then you took it from Coach. And then from a dying deputy.”

Deaton closed his eyes. Selfishly, he found himself wishing that he had never taught Scott about that side of his abilities. Though, he supposed that the teenager inherently cared so much and so deeply for others, he would have discovered it on his own, even without Deaton’s assistance.

Scott McCall was only seventeen years old, and he had every right to be as selfish and self-centered as boys his age often were. Yet without fail, he always considered the well being of others above his own.

It was part of the reason that he rose to the status of True Alpha less than a year after being bitten.

It also made Deaton worry deeply about him, as Scott refused to worry about himself. 

He selected a needle–a large gauge, so there would be little chance of the particulate in the solution clogging at the entry point—and screwed it onto the tip of the syringe.

He was close. Just a few moments more—

“Now,” the Nogitsune’s voice deepened, finally revealing itself as the demon it truly was, “ _ give it to me _ .”

The sounds of struggle and protest cut off, and a chilling silence fell, punctuated only by a harsh, rattling gasp. 

Deaton knew that if a werewolf took too much pain, their system could eventually be overwhelmed, sending them into shock and damaging them beyond the healing capabilities of the body. If pushed too far past their limits, it could even lead to death. 

He didn’t know what would happen to the body if that pain was violently consumed by an ancient spirit of chaos, but it couldn’t be good. 

Time had run out.

Deaton loaded the syringe.

“You really have to learn, Scott. You really have to learn not to trust a fox.”

He tapped the barrel, dispersing any air bubbles.

“Y’know why? ‘Cause they’re tricksters.”

Depressed the plunger slightly. Primed the needle.

“They’ll fool you.”

Done. 

“They’ll fool everyone.”

Deaton hurried into the exam room and—in one clean, practiced motion—injected the contents of the syringe into Stiles’ neck. 

“Not everyone.”

The Nogitsune’s control of its host severed almost instantaneously, and Stiles crumpled to the ground.

The fact that he was immobile on the ground was mildly concerning, as the fully human Stiles should not have been harmed by the lichen. But the teenager didn’t seize or have any other visibly severe reaction, and at this moment the others needed more immediate medical attention. Kira was still unconscious on the ground, and Scott—

Scott was still somehow upright, braced against the exam table. Panting. Face pale, and beaded by both sweat and rain. Impaled by what Deaton could see now was a wakizashi. He hadn’t spoken since Deaton had entered the room.

Deaton wasn’t sure if, in his current state, he was even capable of it.

While not for any physical reason, Deaton felt at a similar loss for words.

Scott’s eyes were wide and panicked, as if he didn’t fully believe that Deaton was really there. Deaton met them with a grave look, because this wasn’t going to be pleasant.

Not for the first time, he wished that supernatural creatures didn’t metabolize anesthetic so quickly.

One glance at Scott’s condition, however, told him that administering anything to mitigate the pain would only serve to prolong his suffering. While removal of the foreign object would be painful, it would allow his body to finally begin healing properly, without the sharp edge of the blade immediately undoing the progress. 

Sometimes, palliative care had to be rejected in favor of the curative treatment. 

He braced a hand lightly on the teenager’s torso, careful not to place it too close to the wound, and with the other pulled the sword out as quickly and cleanly as he could manage. 

Scott still choked back a scream as the blade was yanked free, and Deaton let the offending object clatter to the ground.

A few seconds and several gasping breaths later, Scott finally regained enough of his strength to speak.

Unsurprisingly, the first thing he did was to ask after Stiles. 

“What was that—is that a cure? Is he okay?”

Scott was still panicking, still in pain, but there was hope in his voice now. As if he wanted more than anything to believe that Deaton had simply appeared in the nick of time with the solution to all of their problems. 

Except the lichen wasn’t a cure or even a long-term solution, and despite all his research, Deaton still had no idea how to expel the spirit from Stiles’ body. And he now had the unenviable task of letting Scott down for a second time.

It wasn’t a pain that he had been expecting, but it hurt all the same. 

He settled for as simple an explanation of the truth as he could manage—the details could wait until Scott was at least marginally more healed. “The fox is poisoned, but not dead.” He fixed the body on the floor with a look. “Not yet.” 

It was both a statement of fact, and a promise. One that, if it was in his power, he didn’t intend to break.

At the moment, however, he had more pressing concerns—namely, the three injured teenagers who had found themselves victims of the Nogitsune’s wrath.

Thankfully, the answer to that was simple. They were in his clinic, and he was a doctor.

After confirming that Stiles was only unconscious and not in any immediate danger, he returned to the other two. Scott’s wound still needed to be cleaned and bandaged, but now that the sword had been removed, he seemed to slowly be regaining both strength and color. Satisfied with this—though he still felt a curl of anger twist inside him at the jagged, blood-stained tear in Scott’s shirt and the deep wound that he knew lay beneath it—he turned his attention to Kira instead, as he had seen first hand just how violently her head had impacted against the table.

Scott followed his gaze to where Kira lay on the floor, and guilt flooded his features as the full picture of the past few minutes seemed to rush back. He started to bend down and join Deaton in checking on her, but whatever last measure of control he was holding on to finally gave out, and his knees buckled. 

Deaton saw the movement out of the corner of his eye, and managed to catch him just before he fell, supporting the teen’s weight. He schooled his features as he did, as neither his anger nor his intense concern would be useful in this moment, and might only serve to make Scott feel worse.

He could be angry later.

Once Scott regained his footing, Deaton pulled back, halting any further movement with a gentle hand against his chest. “I wouldn’t do that just yet, if I were you. Those muscles are still healing, and we wouldn’t want to tear anything further.” He glanced down at Kira, who had finally started to stir. “I’ve got her, don’t worry.”

After a brief moment, Scott nodded, and Deaton bent down to help, running his hands behind her head to check for any swelling or lacerations. 

Once he was satisfied that she had no physical injuries, he helped her sit up, watching carefully for signs of a concussion. “How are you feeling? Any dizziness, nausea?”

She shook her head, eyebrows furrowing in confusion. Disoriented, then, but that was to be expected after a loss of consciousness. “Do you remember what happened?”

Kira nodded, concentrating. “My mom… She wouldn’t call off the Oni and we were trying to get in before—” A look of horror crossed her face. “Oh god, Scott!”

She scrambled to her feet, putting to rest any worries that Deaton had about her balance, and rushed to Scott’s side. In fact, she seemed in remarkably good health for someone who had suffered the sort of injury that he had observed, and he wondered privately if her fox spirit had protected her. He didn’t know if she had learned to consciously master her healing abilities yet, but those sorts of things tended to happen automatically when the individual was incapacited. 

Scott, however, was nowhere near in as good physical shape as she was—a fact which Kira seemed to notice almost immediately. She hovered close, worry and fear in her eyes, but never quite touched him.

Her panic only grew when she spotted the sword on the ground, and the small puddle of blood that had formed underneath it.

As the person who had removed the sword only minutes before, Deaton understood the sentiment.

“Oh god, Scott, I’m so sorry, this is all my fault—”

“No, it’s not, I’m—” Scott winced, a hand moving upwards to cover the wound in his abdomen even as he tried to get the words out. “I’ll be okay.”

“Scott, you got  _ stabbed _ —”

“I’ll heal—”

Deaton cut in at this point, because while both teens were correct, there was, at least, something that could be done about this. “Why don’t we see what we can do to speed that process along, shall we?”

Scott nodded, closing his eyes against a wince of pain as he tried and failed to take a deep breath.

Kira glanced over at him again, concerned, before turning back to Deaton. “What can I do?”

“I wouldn’t say no to an extra pair of hands,” he admitted, as he procured a pair of scissors and began to cut Scott’s shirt away from the wound. The request was mainly meant to give Kira something to do, but it also wasn’t a lie—hiring Scott the previous year had taught him that work like this always progressed faster with an assistant. 

He also found, as he described items and their location to Kira and assigned her simple tasks, that the work served to focus and calm him as well. This was something he could do and do well, and together they worked quickly and efficiently. 

He picked stray fibers and torn bits of cloth out of the wound with tweezers, and pointed out to Kira where the tissue at the edges of the wound had already started to knit itself back together. She looked relieved at this, and more than a little awed at the rate of healing. 

Deaton also noted with satisfaction that the tension in Scott’s body drained away as they worked, likely both from a decrease in pain as the wound healed and from adrenaline slowly breaking down and leaving his system. Scott himself, however, was unusually quiet, letting them work with little in the way of comment or protest.

He was staring at Stiles, who still lay unmoving on the ground.

Deaton was taping a large bandage in place when Scott finally spoke. “He’ll—He’ll wake up, right? He’ll be himself?”

He glanced up from his work, and the fear in Scott’s eyes threatened to break his heart for a second time. “To be entirely honest with you, I don’t know for sure. The anti-invasion properties of the lichen should protect his nervous system from the Nogitsune’s attacks, so if he does awake—”

“—He’ll be in control.” Scott finished the thought, a sliver of hope returning to his exhausted features.

“There may be a fight, however,” Deaton cautioned. “Even with the aid of the lichen, I doubt it will cede control either easily or willingly.”

Scott nodded, but a hint of a smile flashed across his face. “I don’t know anyone more stubborn than Stiles is. He can do it.” He looked back over at Stiles. “How long?”

“Will he be in control?” Deaton considered. “Not terribly long, I’m afraid—a few days, at the most. And once the poison’s no longer in his system, there will be nothing to keep the Nogitsune at bay.”

But the hope refused to leave Scott’s eyes. “That’s long enough to buy us time to fix this. To save him.”

Kira didn’t seem quite so convinced, and her eyes once again flicked over to the sword on the floor. “What about the Oni?” 

Thankfully, this was something Deaton could answer with some measure of confidence, given the available evidence. “They haven’t gotten in here yet. And if I’m right, the spirit is suppressed deeply enough that the Oni will no longer immediately recognize him as supernatural.” He looked back at Scott, because he knew the young Alpha had the same fears. “He’ll be safe.”

Safe from the Oni. Safe from the spirit of chaos that burrowed in and made a home inside his mind. And, Scott and the others would be safe from  _ him _ .

Not permanently. Not forever. 

But for now. 

Treating the symptom was invaluable because it provided the time necessary to find a cure.

The bandage finally in place, Deaton watched carefully as Scott stood up straighter, testing muscles that only recently must’ve been screaming in agony. He grimaced as he moved, hand firmly pressed over the bandage, but this time he didn’t fall. When he looked up, his eyes were wide with a mix of fear, desperation, and a determined confidence. “We have to save him.”

Kira moved closer, ready to support his weight with hers, if necessary. “We will.”

As he stepped away to tend to Stiles, Deaton wished that he could share their confidence, but the part of him that was intimately familiar with tragedy and grief was all too aware of the nigh insurmountable task in front of them. 

Yet the more he considered it—remembered Scott’s agonized screams and the torn flesh where the creature literally twisted the knife—the less he could bear the thought of anything resembling a victory for the Nogitsune. 

Stiles was still unconscious, but despite the trauma of an entity invading his body and mind, the boy’s pulse was strong, and his pupils were evenly dilated. If there was a battle for control occurring inside the teenager’s mind, there was at least no indication that he was losing. 

However, while Stiles was unconscious, Deaton suspected that the spirit was very much aware of its surroundings. Locked inside Stiles’ mind and body in much the same way that it had previously kept its host suppressed.

As he worked, he spoke to it quietly.

“I suppose you thought that was impressive,” he said conversationally. “The deception and trickery. Chaos and fear left in your wake. But you made a mistake: you chose the wrong host.” 

He glanced over at Scott, pale and exhausted, but still determined. Kira beside him, helping him to a chair at the other end of the room. “You chose his best friend. And he’s not going to stop until he figures out a way to remove you, permanently. And as for me, well, I’m generally not one to advocate for killing. I prefer to heal.”

Deaton thought about Scott’s ragged screams. The Nogitsune taunting him with razor-sharp words coated in velvet, and the face and voice of his best friend. 

“For you, though? I’m willing to make an exception.”

It was only a matter of time.

**Author's Note:**

> Me? Going to extensive lengths to make mechanisms and processes make sense? It's more likely that you think.
> 
> Also the sheer amount of emotion I have about Deaton and Scott... They deserve so much and I love them.


End file.
